Pivoting hopper for particle blast apparatus

ABSTRACT

A particle blast apparatus has a pivoting hopper, allowing the hopper exit to move from or between a first position at which the exit is aligned with the feeder entrance to a second position where the hopper exit is not aligned as such. The hopper may emptied or cleared in this manner. The hopper may be provided with a device configured to impart energy to the hopper while the hopper exit is located at the second position.

TECHNICAL FIELD

The present invention relates generally to particle blast system, and is particularly directed to a particle blast apparatus comprising a pivoting hopper and to a method of operating a particle blast apparatus which comprises a hopper wherein the hopper exit is moveable between two positions.

BACKGROUND

Particle blasting systems have been around for several decades. Typically, particles, also known as blast media, are fed into a transport gas flow and transported as entrained particles to a blast nozzle, from which the particles exit, being directed toward a workpiece or other target. It is not unknown for the particles to clump or stick together, impeding the delivery of particles into the transport gas flow.

Such compaction and agglomeration of particles is particularly a problem when the blast media is cryogenic particles, such as in carbon dioxide blasting. Although still a relatively young industry, carbon dioxide blasting systems are well known in the industry, and along with various associated component parts, are shown in U.S. Pat. Nos. 4,744,181, 4,843,770, 4,947,592, 5,050,805, 5,018,667, 5,109,636, 5,188,151, 5,301,509, 5,571,335, 5,301,509, 5,473,903, 5,660,580, 5,795,214, 6,524,172 and 6,726,549 all of which are incorporated herein by reference. Although the present invention will be described herein in connection with a particle feeder for use with carbon dioxide blasting, it will be understood that the present invention is not limited in use or application to carbon dioxide blasting. The teachings of the present invention may be used in application in which there can be compaction or agglomeration of any type of particle blast media.

Generally, the blast media particles, such as carbon dioxide particles, are transported from a hopper, which holds the supply of particles, into a transport gas. The particles may be introduced into the transport gas by venturi or other vacuum effect, or by a feeder. Various feeder designs exist, functioning to transport the particles from the hopper exit into the transport gas, such as by the radial transport feeder shown in U.S. Pat. No. 4,947,592. Hoppers may receive particles from any source, such as a pelletizer that is part of the blast system, or a source separate from the blast system and loaded into the hopper. Practice of the present inventions is not limited to a particular type of feeder.

For a variety of reasons, particles may need to be cleared from the hopper from time to time, such as to clear clogs in the hopper or to dispose of unused or unwanted particles without directing them through feeder and ultimately the blast hose. USP '172 discloses and claims a hopper that is moveable from a first position at which the hopper exit is generally aligned with the inlet of a feeder to a second position at which the hopper exit is not aligned with the feeder inlet. The '172 patent discloses that the hopper may be pivoted or moved by translational motion, such as by a parallel rotating framework.

The present invention provides a particle blast apparatus with a unique structure for a pivoting hopper, and a method of operating the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and, together with the general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the present invention.

FIG. 1 is a perspective view of a perspective view of a particle blast apparatus embodying the teachings of the present invention.

FIG. 2 is an enlarged, fragmentary perspective view of the discharge area of the apparatus of FIG. 1.

FIG. 3 is an enlarged, fragmentary perspective view of the discharge area of the apparatus of FIG. 1 with the door omitted.

FIG. 4 is fragmentary side view of the apparatus of FIG. 1, with the outer skin omitted.

FIG. 5 is an enlarged, fragmentary side view of the apparatus of FIG. 1, showing the hopper exit and the feeder inlet, and the discharge area in partial cross section.

FIG. 6 is a fragmentary side view of the apparatus of FIG. 1, illustrating the hopper pivoted to a hopper discharge position.

FIG. 7 is an enlarged, fragmentary side view of the apparatus of FIG. 1, illustrating the hopper pivoted to the hopper discharge position, showing the hopper exit and feeder inlet, and the discharge area.

FIG. 8 is a bottom perspective view of the apparatus of FIG. 1, with the hopper and most of the skin omitted.

FIG. 9 is a side perspective view of the apparatus of FIG. 1.

FIG. 10 is an exploded perspective view of the apparatus of FIG. 1.

FIG. 11 is an enlarged, fragmentary perspective view of a portion of the support members of the apparatus of FIG. 1.

Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings.

DETAILED DESCRIPTION

In the following description, like reference characters designate like or corresponding parts throughout the several views. Also, in the following description, it is to be understood that terms such as front, back, inside, outside, and the like are words of convenience and are not to be construed as limiting terms. Terminology used in this patent is not meant to be limiting insofar as devices described herein, or portions thereof, may be attached or utilized in other orientations. Referring in more detail to the drawings, an embodiment of the invention will now be described.

Referring to FIGS. 1, particle blasting apparatus is generally indicated at 2. Apparatus 2 includes pivoting cover 4 which overlies the charging area of hopper 6 (see FIG. 4), which in the embodiment depicted is attached to hopper 6 by hinge 8. Apparatus 2 includes discharge area generally indicated at 10, through which particles being cleared from hopper 6 may be discharged. Referring also to FIGS. 2 and 3, in the embodiment depicted, discharge area 10 may include door 12 (omitted from FIG. 3 for clarity), which may, as shown, be hinged at the top and may be biased toward the closed or vertical position.

Apparatus 2 may include devices to impart mechanical energy to hopper 6 to cause vibrations in hopper 6, although the pivoting hopper configuration of the present invention is not limited to use with any such energy imparting devices. FIG. 4 depicts two energy imparting devices carried by hopper 6. Impulse assembly 14, such as described in U.S. Pat. No. 6,726,549, shown carried by hopper 6, is, in the embodiment depicted, configured to selectively impart impulse energy to hopper 6 at intervals, during blasting operations or during clearing discharges (as will be described below). While actuated, assembly 14 provides impulse energy to hopper 6. The intervals may be of any length, whether identical, varying or even random. The amount of energy delivered by assembly 14 may be constant or varied. Continuous energy assembly 16, such as described in U.S. Pat. No. 6,726,549, shown carried by hopper 6, is, in the embodiment depicted, configured to selectively impart continuous energy to hopper 6 during blasting operations or during clearing discharges (as will be described below). While actuated, assembly 16 provides continuous energy to hopper 6 at energy at energy levels, frequencies (continuous or variable) and duty cycles as may be suitable. Although it is desirable for hopper 6 to carry assemblies 14 and 16 directly, assemblies 14 and 16 may be mounted elsewhere while still configured to deliver energy to hopper 6.

Referring to FIGS. 4 and 5, hopper 6 includes at its lower hopper exit 18, from which particles are discharged. Exit 18 is shown aligned with entrance 20 of feeder assembly 22, with seal 24 disposed therebetween, seating against feeder assembly 22 adjacent entrance 20. Seal 24 may be of any suitable configuration, such as is in U.S. Pat. No. 6,726,549. 0During blasting operations, exit 18 is disposed at a first position, such as illustrated in FIGS. 4 and 5, at which hopper exit 18 is generally aligned with entrance 20 so as to deliver particles directly to feeder assembly 22, or indirectly in the event of additional structure between hopper exit 18 and entrance 20, for entrainment in the transport gas flow.

Referring to FIGS. 6 and 7, hopper 6 is moveable from its supply operation position shown in FIGS. 4 and 5 to a second position at which hopper exit 18 is not aligned with feeder entrance 20. At the second position, hopper 6 may be emptied or cleared. As seen in FIGS. 6 and 7, door 12 has been pivoted outwardly by the lower end of hopper 6, in particular in the embodiment depicted, by part of the assembly of seal 24. Wear pad 26 may be disposed inside of door 12 in a position to be engaged by the seal assembly, or alternatively by any suitable structure configured to engage and rotate door 12 outwardly. At the position illustrated in FIGS. 6 and 7, exit 18 is disposed such that particles within hopper 6 may be discharged outside of apparatus 2. Discharge area 10 may be, as seen in the embodiment depicted, configured as a chute such that particles are guided outside of apparatus 2. Chute may be formed by suitably shaped panels 28, secured in any suitable manner, such as by fasteners 30. Fasteners 30 could also be configured to be flush or nearly flush to panel 28 to present a flat profile.

As hopper 6 is pivoted from the first position to the second position, seal 24 disengages feeder 22. As will be described below, the pivot axis of hopper 6 is preferably located relative to exit 18 and feeder 22 such that the movement of exit 18 is away from feeder 22. Such an orientation results in lateral translation of seal 24 as it slides along upper surface 22 a, and a reduction in the force biasing seal 24 against upper surface 22 a as springs 24 a extend, until such time as the rotation of hopper 6 produces complete disengagement of seal 24 from upper surface 22 a. This configuration avoids increasing the force between seal 24 and upper surface 22 a during rotation. It should be noted that although believed to be undesirable, the pivot axis of hopper 6 could be disposed such that such force between seal 24 and upper surface 22 a does increase if the force preferably does not reach a level that results in premature failure of any components.

FIG. 8 illustrates the pivotable mechanism configured to allow hopper 6 to be selectively pivoted. Particle blast apparatus 2 includes main frame 32 which supports pivotable subframe 34. Referring also to FIGS. 9 and 10, subframe 34 comprises spaced apart support members 36 a and 36 b, disposed on opposite sides of hopper 6, with member 36 c extending between proximal ends of support members 36 a and 36 b. Subframe 34 includes arms 38 a and 38 b depending downwardly from support members 36 a and 36 b, respectively. Pivots 40 a and 40 b extend outwardly from support members 36 a and 36 b, respectively. Stops 42 a and 42 b extend downwardly from respective brackets 44 a and 44 b mounted to subframe 34 as shown. As shown in the embodiment depicted, stops 42 a and 42 b may be configured to be adjustable, such as by external threads on stops 42 a and 42 b engaging internal threads formed in brackets 44 a and 44 b. The distal ends of stops 42 a and 42 b may comprise a wear resistant and/or resilient material. As shown in the embodiment depicted, plates 46 a and 46 b may be secured to main frame 32 in any suitable manner, aligned with stops 42 a and 42 b such that main frame 32 is not worn by pivoting hopper 6.

In the depicted embodiment, pivots are depicted as pins 40 a and 40 b which are respectively rotatably received by complementarily shaped openings 48 a and 48 b of bearing blocks 50 a and 50 b, respectively. Bearing blocks 50 a and 50 b may be made of any suitable material, such as HDPE and secured to main frame 32 in any suitable manner, such as by threaded fastener. Each bearing block 50 a, 50 b may include one or more additional openings shaped complementary to pivot pins 40 a and 40 b so that in the event openings 48 a and/or 48 b become excessively worn, either bearing block 50 a or 50 b may be reoriented such that openings 52 a and/or 52 b receive pivot pin pivot pin 40 a and/or 40 b. This avoids having to order and replace bearing block 50 a or 50 b once the first used pivot pin opening wears out.

Each support member 36 a and 36 b and main frame 32 may respectively be configured to locate subframe 34 laterally relative to main frame 32. Any suitable configuration may be used. Referring to FIG. 11, support member 36 a in the embodiment depicted comprises laterally extending bracket 54 a with a longitudinally extending opening or slot 56 a. (Although support member 36 b is not seen in FIG. 11, its configuration is a mirror image of support member 36 a and bracket 54 a.) Referring also to FIG. 10, main frame 32 includes upwardly extending members 58 a and 58 b. Slot 56 a receives pin 58 a so as to limit lateral movement and locate hopper laterally.

Referring to FIGS. 10 and 11, hopper 6 is carried by but isolated from subframe 34 in a manner that minimizes transfer of mechanical energy from hopper 6. As seen in FIGS. 10 and 11, a plurality of isolators 60 are interposed between subframe 34 and hopper 6. In the embodiment depicted, isolators 60 are spaced apart disposed at non-contiguous locations such that the center of gravity of hopper, empty or full, falls within the footprint or plan area of isolators 60. During blast operations, isolators 60 are in compression with the loading being essentially vertical.

Isolators 60 may be secured to subframe 34 and hopper 6 in any suitable manner. In the embodiment depicted, isolators 60 include threaded shafts 60 a which extend in opposite direction from the middle portions of isolators 60. The downwardly depending threaded shafts 60 a are disposed through openings 62 formed in subframe 34 and secured thereto by nuts 64. Similarly, the upwardly extending threaded shafts 60 a are received by openings 66 formed in flanges 6 a and 6 b (on side opposite flange 6 a, not illustrated) of hopper 6. Nuts 68 secure flanges 6 a and 6 b to isolators 60.

Alternatively to, or in addition to, the use of isolators 60, isolation of hopper 6 to minimize from the rest of apparatus 2 may occur between pivot pins 40 a and 40 b and main frame 32. For example, isolation may be provided between bearings 50 a and 50 b and main frame 32.

Referring to FIG. 10, actuators 70 a and 70 b are used to effect pivoting of subframe 34 and concomitantly hopper 6. In the embodiment depicted, actuators 70 a and 70 b are double acting pneumatic cylinders, although any suitable actuator and any suitable configuration may be used. In the embodiment depicted, ends 72 a and 72 b of actuators 70 a and 70 b, respectively, are pivotably connected to the distal ends of arms 38 a and 38 b, respectively. Ends 74 a and 74 b of actuators 70 a and 70 b, respectively, are pivotably connected to brackets 76 a and 76 b which are secured to main frame 32.

In the embodiment depicted, during blast operations, actuators 70 a and 70 b bias hopper 6 in the first position whereat hopper exit 18 is aligned with feeder entrance 20 with a force of about 80 lbf (axially relative to actuators 70 a and 70 b). In the embodiment depicted, this is accomplished by applying the force to arms 38 a and 38 b, and thereby to subframe 36. To empty or clear hopper 6, actuators are actuated to cause hopper 6 to pivot to move hopper exit 18 to a second position at which hopper exit 18 is not aligned with feeder entrance 20. In the embodiment depicted, actuators 70 a and 70 b bias hopper exit 18 to discharge area 10. Rotation of hopper 6 is limited by the engagement of stops 42 a and 42 b with plates 46 a and 46 b (see FIG. 6). At this second position, hopper 6 may be emptied or cleared.

A method of operating particle blast apparatus 2 includes the steps of applying energy to hopper 6 while hopper exit 18 is located at discharge area 10 to assist in dislodging particles from hopper 6 for discharge. This may be accomplished by activating energy assemblies 14 and 16, either simultaneously, separately or sequentially, while hopper exit 18 is disposed at the discharge area 10.

The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiment was chosen and described in order to best illustrate the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims submitted herewith. 

1. A method of operating a particle blast apparatus, said particle blast apparatus having a hopper, the hopper having an exit, and having a particle feeder having an inlet for receiving particles, the exit being disposable at a first position at which the exit is not aligned with said inlet, comprising the step of applying energy to said hopper while said exit is disposed at side first position.
 2. The method of claim 1, wherein said step of applying energy comprises the step of applying mechanical energy.
 3. The method of claim 1, wherein the energy applied during said step of applying energy is applied as impulses.
 4. The method of claim 1, wherein the energy applied during said step of applying energy is applied continuously.
 5. The method of claim 1, wherein the energy applied during said step of applying energy is applied as impulses and as continuous energy.
 6. A particle blast apparatus, comprising: a. a particle feeder having an inlet for receiving particles; b. a hopper having an exit, said hopper being pivotable about a pivot axis between a first hopper position at which said exit is at a first exit position at which said exit is aligned with said inlet, and a second hopper position at which said exit is disposed at a second exit position at which said exit is not aligned with said inlet; and c. said pivot axis being disposed relative to said exit such that said exit does not move toward said inlet as said hopper moves from said first hopper position toward said second hopper position.
 7. The particle blast apparatus of claim 6, further comprising a seal carried by said hopper adjacent said exit and disposed to sealingly engage said inlet when said exit is disposed at said first exit position, said pivot axis being disposed relative to said exit such that force between said seal and said inlet does not substantially increase as said hopper moves from said first hopper position toward said second hopper position.
 8. The particle blast apparatus of claim 7, wherein said force does not increase as said hopper moves from said first hopper position toward said second hopper position.
 9. The particle blast apparatus of claim 6, further comprising: a. a first frame, said first frame carrying said particle feeder; and b. a second frame, said second frame carrying said hopper, said second frame being pivotably carried by said first frame.
 10. The particle blast apparatus of claim 9, wherein said second frame comprises: a. first and second spaced apart support members disposed on either side of said hopper; b. first and second pivots carried respectively extending from said first and second members; c. said first and second pivots rotatably supported by said first frame.
 11. The particle blast apparatus of claim 10, comprising first and second bearings carried by said first frame, and wherein said first and second pivots respectively comprise first and second pins, said first and second pins being rotatably carried by said first and second bearings respectively.
 12. A particle blast apparatus, comprising: a. a particle feeder having an inlet for receiving particles; b. a hopper having an exit, said hopper being pivotable about a pivot axis between a first hopper position at which said exit is at a first exit position at which said exit is aligned with said inlet, and a second hopper position at which said exit is disposed at a second exit position at which said exit is not aligned with said inlet; and c. a pivotable door disposed adjacent said second hopper position, said door being moveable between a first and second position, said door disposed such that as said hopper is moved toward said second hopper position said hopper moves said door toward said second position.
 13. The particle blast apparatus of claim 12, wherein said door is biased toward said first position.
 14. The particle blast apparatus of claim 12, comprising a wear pad carried by said door, said wear pad disposed to be engaged by said hopper when said hopper moves said door toward said second position. 